The following disclosure relates to an electric-brake controller configured to control an electric brake activated by an electric motor and to a vehicle brake system including the electric-brake controller.
Patent Document 1 (Japanese Patent Application Publication No. 2005-247306) discloses an electric-brake controller configured to control an electric brake. In the electric brake disclosed in Patent Document 1, rotation of the electric motor in a forward direction advances the pressing member, and a pair of friction pads are pressed against a rotor, resulting in reduced rotation of a wheel. The electric brake is provided with a return spring configured to apply a spring force to the pressing member so as to move the pressing member backward.
In the case where anti-lock control is executed by an electric-brake controller disclosed in Patent Document 1, a sharp reduction mode is set in the case where deviation obtained by subtracting an actual slip rate from a target slip rate is less than −e1, a gentle reduction mode is set in the case where the deviation has become greater than −e2(−e1 <−e2), and a sharp increase mode is set in the case where the deviation has become greater than −e3(−e3 >−e2). In the case where each of the sharp reduction mode and the gentle reduction mode is set, current for rotating the electric motor reversely is supplied to the electric motor. In the case where the sharp increase mode is set, current for rotating the electric motor forwardly is supplied to the electric motor.